The House of Palaiologos (pl. Palaiologoi; Ancient Greek: Παλαιολόγος, pl. Παλαιολόγοι; female version Palaiologina; Ancient Greek: Παλαιολογίνα), also found in English-language literature as Palaeologus or Palaeologue, was a Byzantine Greek noble family that rose to power and produced the last and longest-ruling dynasty in the history of the Roman Empire. Their rule as Byzantine emperors lasted almost two hundred years, from 1259 to the fall of Constantinople in 1453.
The origins of the family are unclear. Their own medieval origin stories ascribed them an ancient and prestigious origin in ancient Roman Italy, descended from some of the Romans that had accompanied Constantine the Great to Constantinople upon its foundation in 330. It is more likely that they originated significantly later in Anatolia since the earliest known member of the family, possibly its founder, Nikephoros Palaiologos, served as a commander there in the second half of the 11th century. Over the course of the 12th century, the Palaiologoi were mostly part of the military aristocracy, not recorded as occupying any administrative political offices, and they frequently intermarried with the then ruling Komnenos family, increasing their prestige. When Constantinople fell to the Fourth Crusade in 1204, the Palaiologoi fled to the Empire of Nicaea, a Byzantine successor state ruled by the Laskaris family, where they continued to play an active role and occupied many offices of high rank.
